MADRID — A Spanish judge ordered the release Thursday of a U.S. citizen of Algerian origin who was detained on suspicion of financing al-Qaida’s North Africa affiliate, citing a lack of evidence but keeping the investigation open.

LONDON — European security officials said Wednesday a terror plot to wage Mumbai-style shooting sprees in Britain, France and Germany is still active and that sites in Pakistan — where the threat was intercepted two weeks ago — are being scoured for al-Qaida operatives.